Bulugh al-Maram #144

Narrated ‘Aisha (rad): Whenever Allah’s Messenger (ﷺ) took Ghusl (bath) after sexual intercourse, he would begin by washing his hands, then pour water with his right hand on his left hand and wash his sexual organ. He would then perform ablution, then take some water and run his fingers through the roots of the hair. Then he would pour three handfuls on his head, then pour water over the rest of his body and subsequently wash his feet.